FBI Director James Comey argued privately that it was too close to Election Day for the United States government to name Russia as meddling in the U.S. election and ultimately ensured that the FBI's name was not on the document that the U.S. government put out, a former FBI official tells CNBC.

The official said some government insiders are perplexed as to why Comey would have election timing concerns with the Russian disclosure but not with the Huma Abedin email discovery disclosure he made Friday.